Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study.

AIM: This study compared the quality and quantity of newly formed bone in rabbits' critical-sized calvarial defects filled with enamel matrix derivative (EMD) combined with freeze-dried bone allograft (FDBA) vs FDBA alone. MATERIALS AND METHODS: A total of 24 adult male white New Zealand rabbits were included. In each rabbit, three bone defects with a diameter of 8 mm were created on the calvarium bone; the first defect was left untreated, while the second was filled with FDBA, and the third was filled with EMD + FDBA. Twelve rabbits were randomly euthanized after a month, and the remaining 2 month postsurgery. Bone sections were histologically evaluated by hematoxylin and eosin and vascular endothelial growth factor (VEGF), alkaline phosphatase (ALP), osteoprotegerin (OPG), and receptor activator of NF-kappaB (RANK) immune-histochemical staining. RESULTS: An improvement in the newly formed bone percentage was found in the defects filled with EMD + FDBA in comparison with FDBA and control defects at 1 month and 2 months postsurgery. Additionally, the expression of VEGF, ALP, OPG, and RANK showed highly significant differences in the defects filled with EMD + FDBA compared to the FDBA and control ones at 1 month postsurgery (p = 0.001). Meanwhile, VEGF and ALP expression showed a significant decrease in defects filled with EMD + FDBA compared to the FDBA and control ones (p = 0.001), while OPG and RANK expression showed non-significant differences between treated groups at 2 months postsurgery. CONCLUSION: Enamel matrix derivative combined with FDBA has a synergistic effect on bone formation and graft substitution. This combination accelerates the expression of VEGF, ALP, OPG, and RANK. CLINICAL SIGNIFICANCE: The combination of EMD and FDBA accelerates and ameliorates the quality of newly formed bone, aiding in maxillofacial reconstruction. How to cite this article: Zakri RN, Grawish ME, Mowafey B, et al. Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study. J Contemp Dent Pract 2024;25(5):424-431.

Osteoprotegerin and RANKL-RANK-OPG-TRAIL signalling axis in heart failure and other cardiovascular diseases.

Osteoprotegerin (OPG) is a glycoprotein involved in the regulation of bone remodelling. OPG regulates osteoclast activity by blocking the interaction between the receptor activator of nuclear factor kappa B (RANK) and its ligand (RANKL). More and more studies confirm the relationship between OPG and cardiovascular diseases. Numerous studies have confirmed that a high plasma concentration of OPG and a low concentration of tumour necrosis factor-related apoptosis inducing ligand (TRAIL) together with a high OPG/TRAIL ratio are predictors of poor prognosis in patients with myocardial infarction. A high plasma OPG concentration and a high ratio of OPG/TRAIL in the acute myocardial infarction are a prognostic indicator of adverse left ventricular remodelling and of the development of heart failure. Ever more data indicates the participation of OPG in the regulation of the function of vascular endothelial cells and the initiation of the atherosclerotic process in the arteries. Additionally, it has been shown that TRAIL has a protective effect on blood vessels and exerts an anti-atherosclerotic effect. The mechanisms of action of both OPG and TRAIL within the cells of the vascular wall are complex and remain largely unclear. However, these mechanisms of action as well as their interaction in the local vascular environment are of great interest to researchers. This article presents the current state of knowledge on the mechanisms of action of OPG and TRAIL in the circulatory system and their role in cardiovascular diseases. Understanding these mechanisms may allow their use as a therapeutic target in cardiovascular diseases in the future.

Psychostimulants Modafinil, Atomoxetine and Guanfacine Impair Bone Cell Differentiation and MSC Migration.

Attention deficit hyperactivity disorder (ADHD) is one of the most common worldwide mental disorders in children, young and adults. If left untreated, the disorder can continue into adulthood. The abuse of ADHD-related drugs to improve mental performance for studying, working and everyday life is also rising. The potentially high number of subjects with controlled or uncontrolled use of such substances increases the impact of possible side effects. It has been shown before that the early ADHD drug methylphenidate influences bone metabolism negatively. This study focused on the influence of three more recent cognitive enhancers, modafinil, atomoxetine and guanfacine, on the differentiation of mesenchymal stem cells to osteoblasts and on their cell functions, including migration. Human mesenchymal stem cells (hMSCs) were incubated with a therapeutic plasma dosage of modafinil, atomoxetine and guanfacine. Gene expression analyses revealed a high beta-2 adrenoreceptor expression in hMSC, suggesting it as a possible pathway to stimulate action. In bone formation assays, all three cognitive enhancers caused a significant decrease in the mineralized matrix and an early slight reduction of cell viability without triggering apoptosis or necrosis. While there was no effect of the three substances on early differentiation, they showed differing effects on the expression of osterix (OSX), receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in the later stages of osteoblast development, suggesting alternative modes of action. All three substances significantly inhibited hMSC migration. This effect could be rescued by a selective beta-blocker (Imperial Chemical Industries ICI-118,551) in modafinil and atomoxetine, suggesting mediation via beta-2 receptor stimulation. In conclusion, modafinil, atomoxetine and guanfacine negatively influence hMSC differentiation to bone-forming osteoblasts and cell migration through different intracellular pathways.

New Generation of Meso and Antiprogestins (SPRMs) into the Osteoporosis Approach.

Receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) play key roles in bone metabolism and the immune system. The RANK/RANKL complex has also been shown to be critical in the formation of mammary epithelia cells. The female hormones estradiol and progesterone closely control the action of RANKL with RANK. Blood concentration of these sex hormones in the postmenopausal period leads to an increase in RANK/RANKL signaling and are a major cause of women's osteoporosis, characterized by altered bone mineralization. Knowledge of the biochemical relationships between hormones and RANK/RANKL signaling provides the opportunity to design novel therapeutic agents to inhibit bone loss, based on the anti-RANKL treatment and inhibition of its interaction with the RANK receptor. The new generation of both anti- and mesoprogestins that inhibit the NF-κB-cyclin D1 axis and blocks the binding of RANKL to RANK can be considered as a potential source of new RANK receptor ligands with anti-RANKL function, which may provide a new perspective into osteoporosis treatment itself as well as limit the osteoporosis rise during breast cancer metastasis to the bone.

Microsphere controlled drug delivery for local control of tooth movement.

Background: Because orthodontic tooth movement is dependent upon osteoclast-mediated resorption of alveolar bone adjacent to the pressure side of tooth roots, biologic mediators that regulate osteoclasts can be utilized to control tooth movement. Objectives: To develop a novel method to locally enhance orthodontic anchorage. Methods: We encapsulated osteoprotegerin (OPG) in polymer microspheres and tested the effectiveness of microsphere encapsulated versus non-encapsulated OPG for enhancing orthodontic anchorage in a rodent model of tooth movement. A single injection of 1 mg/kg non-encapsulated or microsphere encapsulated OPG was delivered into the palatal mucosa mesial to the first maxillary molar 1 day prior to tooth movement. A positive control group received injections of 5 mg/kg non-encapsulated OPG every 3 days during tooth movement. After 28 days of tooth movement, hemi-maxillae and femurs were dissected. Molar mesial and incisor distal tooth movement was measured using stone casts that were scanned and magnified. Local alveolar, distant femur bone, and tooth root volumes were analyzed by micro computed tomography. Serum OPG levels were measured by ELISA. Osteoclast numbers were quantified by histomorphometry. Results: The single injection of microsphere encapsulated OPG significantly enhanced orthodontic anchorage, while the single injection of non-encapsulated OPG did not. Injection of encapsulated OPG inhibited molar mesial movement but did not inhibit incisor tooth movement, and did not alter alveolar or femur bone volume fraction, density, or mineral content. Multiple injections of 5 mg/kg non-encapsulated OPG enhanced orthodontic anchorage, but also inhibited incisor retraction and altered alveolar and femur bone quality parameters. Increased OPG levels were found only in animals receiving multiple injections of non-encapsulated 5 mg/kg OPG. Osteoclast numbers were higher upon tooth movement in animals that did not receive OPG. Osteoclast numbers in OPG injected animals were variable within groups. Conclusions: Microsphere encapsulation of OPG allows for controlled drug release, and enhances site-specific orthodontic anchorage without systemic side effects. With additional refinements, this drug delivery system could be applicable to a broad array of potential biologic orthodontic therapeutics.

Osteoprotegerin and ß2-Agonists Mitigate Muscular Dystrophy in Slow- and Fast-Twitch Skeletal Muscles.

Our recent work showed that daily injections of osteoprotegerin (OPG)-immunoglobulin fragment complex (OPG-Fc) completely restore the function of fast-twitch extensor digitorum longus muscles in dystrophic mdx mice, a murine model of Duchenne muscular dystrophy. However, despite marked improvements, OPG-Fc was not as effective in preventing the loss of function of slow-twitch soleus and diaphragm muscles. Because ß2-agonists enhance the function of slow- and fast-twitch dystrophic muscles and because their use is limited by their adverse effects on bone and cardiac tissues, we hypothesized that OPG-Fc, a bone and skeletal muscle protector, acts synergistically with ß2-agonists and potentiates their positive effects on skeletal muscles. We observed that the content of ß2-adrenergic receptors, which are mainly expressed in skeletal muscle, is significantly reduced in dystrophic muscles but is rescued by the injection of OPG-Fc. Most important, OPG-Fc combined with a low dose of formoterol, a member of a new generation of ß2-agonists, histologically and functionally rescued slow-twitch dystrophic muscles. This combination of therapeutic agents, which have already been tested and approved for human use, may open up new therapeutic avenues for Duchenne muscular dystrophy and possibly other neuromuscular diseases.

Role of vascular calcification inhibitors in preventing vascular dysfunction and mortality in hemodialysis patients.

Cardiovascular events make up the primary cause of death in hemodialysis patients, and the risk for cardiovascular mortality is significantly increased by vascular calcification, a condition observed frequently in this patient population. The mechanisms underlying the pathogenesis of vascular calcification are complex, and many factors facilitate or hinder the development of calcification. In this review, we first summarize the main factors contributing to the pathogenesis of vascular calcification in patients with end-stage renal disease. We then explore the role of calcification inhibitors in the calcification process, as well as their effect on vascular dysfunction and mortality in hemodialysis patients.

Therapeutic and Preventive Effects of Osteoclastogenesis Inhibitory Factor on Osteolysis, Proliferation of Mammary Tumor Cell and Induction of Cancer Stem Cells in the Bone Microenvironment.

BACKGROUND: We examined the effects of recombinant human osteoclastogenesis inhibitory factor (hOCIF) on osteolysis, proliferation of mammary tumor cells, and induction of cancer stem cells (CSCs) in the tumor-bone and tumor-subcutaneous microenvironments (TB- and TS-microE). METHODS: Mouse mammary tumor cells were transplanted onto the calvaria or into a subcutaneous lesion of female mice, creating a TB-microE and a TS-microE, and the mice were then treated with hOCIF. To investigate the preventive effects of hOCIF, mice were treated with hOCIF before tumor cell implantation onto the calvaria (Pre), after (Post), and both before and after (Whole). The number of CSCs and cytokine levels were evaluated by IHC and ELISA assay, respectively. RESULTS: hOCIF suppressed osteolysis, and growth of mammary tumors in the TB-microE, but not in the TS-microE. In the Pre, Post, and Whole groups, hOCIF suppressed osteolysis, and cell proliferation. hOCIF increased mouse osteoprotegrin (mOPG) levels in vivo, which suppressed mammary tumor cell proliferation in vitro. These preventive effects were observed in the dose-dependent. hOCIF did not affect the induction of CSCs in either microenvironment. CONCLUSION: While receptor activator of NF-κB ligand (RANKL) targeting therapy may not affect the induction of CSCs, RANKL is a potential target for prevention as well as treatment of breast cancer bone metastasis.

In vivo osteoprotegerin gene therapy preventing bone loss induced by periodontitis.

OBJECTIVE: The objective of this study was to investigate the effects of osteoprotegerin (OPG) gene therapy on alveolar bone resorption caused by experimental periodontitis in rats, thus forming a foundation for potential clinical applications of OPG gene therapy in the treatment of periodontitis and peri-implantitis. MATERIAL AND METHODS: To study the effects of OPG on alveolar bone protection, an experimental periodontitis model was used by placing a bacterial plaque retentive silk ligature in the gingival sulcus around the maxillary second molar tooth, injection of Porphyromonas gingivalis and high carbohydrate diet. A total of 30 Sprague-Dawley rats were randomly divided into three groups, with 10 rats in each group: group I (control) was treated with 10 µL normal saline injection; group II with 10 µL mock vector; and group III with 10 µL local OPG gene transfer by transfection with in vitro constructed pcDNA3.1-human OPG (pcDNA3.1-hOPG). A subperiosteal injection was done adjacent to the second molars on days 0, 7, 14 and 21. Four weeks later, all animals were killed and radiographic, histological and immunohistochemical examinations were performed. Statistical analysis included ANOVA and LSD-Bonferroni test. RESULTS: Group III (OPG gene therapy) had significantly enhanced (p < 0.05) integrated optical density of OPG, had significantly decreased alveolar bone resorption volume and active osteoclast number (p < 0.05) through descriptive histological examination when compared with the other two groups at week 4. CONCLUSION: Local recombinant OPG plasmid-mediated gene therapy suppresses osteoclastogenesis in vivo and inhibits alveolar bone height reduction caused by experimental periodontitis in rats. OPG gene therapy may be beneficial in preventing progressive periodontal bone loss.

Locally limited inhibition of bone resorption and orthodontic relapse by recombinant osteoprotegerin protein.

OBJECTIVES: To determine minimal dose levels required for local inhibition of orthodontic relapse by recombinant OPG protein (OPG-Fc), while also determining effects of injected OPG-Fc on alveolar bone and long bone. SETTING AND SAMPLE POPULATION: The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Eighteen male Sprague Dawley rats. MATERIALS & METHODS: Maxillary molars were moved with nickel-titanium springs and then allowed to relapse in Sprague Dawley rats. Upon appliance removal, animals were injected with a single dose of 1.0 mg/kg OPG-Fc, 0.1 mg/kg OPG-Fc, or phosphate-buffered saline (vehicle) just distal to the molar teeth. Tooth movement measurements were made from stone casts, which were scanned and digitally measured. Alveolar tissues were examined by histology. Micro-computed tomography was used to quantify changes in alveolar and femur bone. RESULTS: Local injection of OPG-Fc inhibited molar but not incisor relapse, when compared to vehicle-injected animals. No significant differences in alveolar or femur bone were seen between the three treatment groups after 24 days of relapse. CONCLUSIONS: Our results demonstrate that a single local injection of OPG-Fc effectively inhibits orthodontic relapse, with minimal systemic bone metabolic effects. Our results also show that a single injection of OPG-Fc will influence tooth movement only in teeth close to the injection site. These findings indicate that OPG-Fc has potential as a safe and effective pharmacological means to locally control osteoclasts, for uses such as maintaining anchorage during orthodontic tooth movement and preventing orthodontic relapse in humans.

An experimental therapy to improve skeletal growth and prevent bone loss in a mouse model overexpressing IL-6.

UNLABELLED: Premature osteoporosis and stunted growth are common complications of childhood chronic inflammatory disease. Presently, no treatment regimens are available for these defects in juvenile diseases. We identified the sequential Fc-OPG/hPTH treatment as an experimental therapy that improves the skeletal growth and prevents the bone loss in a mouse model overexpressing IL-6. INTRODUCTION: Premature osteoporosis and stunted growth are common complications of childhood chronic inflammatory diseases and have a significant impact on patients' quality of life. Presently, no treatment regimens are available for these defects in juvenile diseases. To test a new therapeutic approach, we used growing mice overexpressing the pro-inflammatory cytokine IL-6 (TG), which show a generalized bone loss and stunted growth. METHODS: Since TG mice present increased bone resorption and impaired bone formation, we tested a combined therapy with the antiresorptive modified osteoprotegerin, Fc-OPG, and the anabolic PTH. We injected TG mice with Fc-OPG once at the 4th day of life and with hPTH(1-34) everyday from the 16th to the 30th day of age. RESULTS: A complete prevention of growth and bone defects was observed in treated mice due to normalization of osteoclast and osteoblast parameters. Re-establishment of normal bone turnover was confirmed by RT-PCR analysis and by in vitro experiments that revealed the full rescue of osteoclast and osteoblast functions. The phenotypic recovery of TG mice was due to the sequential treatment, because TG mice treated with Fc-OPG or hPTH alone showed an increase of body weight, tibia length, and bone volume to intermediate levels between those observed in vehicle-treated WT and TG mice. CONCLUSIONS: Our results identified the sequential Fc-OPG/hPTH treatment as an experimental therapy that improves the skeletal growth and prevents the bone loss in IL-6 overexpressing mice, thus providing the proof of principle for a therapeutic approach to correct these defects in juvenile inflammatory diseases.

Bone metastasis: can osteoclasts be excluded?

The RANK/RANKL signalling mechanism is the final common pathway of osteoclast formation and activity. Inhibitors of RANK ligand (RANKL) that bind to RANK (for 'receptor activator of NF-kappaB'), such as osteoprotegerin (OPG), neutralizing antibodies against RANKL and soluble RANK antagonists, are well described inhibitors of bone metastasis in preclinical and clinical models, presumably because of their effects on osteoclasts. Jones et al. show that OPG inhibits bone metastasis after intracardiac injection of B16F10 murine melanoma cells, but claim that bone metastases are entirely independent of osteoclast formation and bone resorption: rather, they are caused by an effect on cell migration through RANK. However, we question whether these surprising conclusions are rigorously supported by their data.

Local delivery of recombinant osteoprotegerin enhances postorthodontic tooth stability.

Relapse after orthodontic tooth movement is a significant problem in orthodontics. The purpose of this study was to examine the efficacy of the osteoclast inhibitor osteoprotegerin-Fc (OPG-Fc) for inhibiting postorthodontic relapse. Rat maxillary molars were moved mesially and allowed to relapse for 24 days. Low-dose (1 mg/kg) or high-dose (5 mg/kg) OPG-Fc or saline was injected adjacent to the molars during relapse. Tooth movement, micro-CT, histologic bone quality, and serum OPG and TRAP-5b were measured. OPG-Fc injections significantly diminished postorthodontic relapse from 63% (0.78/1.20 mm) of total movement in vehicle control rats to 31% (0.31/1.00 mm) in low-dose and 24% (0.28/1.16 mm) in high-dose OPG-Fc groups 24 days after appliance removal. Normalization of bone and periodontal tissues occurred as early as 8 and 16 days in the high- and low-dose OPG-Fc-treated groups, respectively, while the vehicle-treated group showed only partial tissue recovery 24 days following tooth movement. After 24 days of relapse, there was complete recovery to pre-tooth-movement values for bone volume fraction (BVF) and tissue mineral density (TMD) in both the low- and high-dose OPG-Fc groups, while BVF recovered only partially and TMD did not recover in the vehicle control group. Greatly elevated serum OPG levels and reduced serum TRAP-5b levels in OPG-Fc-treated animals indicated systemic exposure to locally injected drug. The profound decrease in postorthodontic relapse by local OPG-Fc administration indicates that osteoclasts are critical to bone maturation following tooth movement and points to the potential pharmacologic use of OPG-Fc or other RANKL inhibitors for orthodontic retention.

Exploration of the Effect of Icariin on Nude Mice with Lung Cancer Bone Metastasis via the OPG/RANKL/RANK System.

Epimedium is a traditional Chinese medicine that is most commonly prescribed by practitioners of Chinese medicine for the clinical treatment of malignant tumor bone metastasis. The main component of Epimedium is icariin (ICA). Studies have shown that ICA inhibits bone resorption of osteoclasts through the OPG/RANKL/RANK signaling pathway. Osteoclasts are the only cells in the body that have a bone-destroying capability. The OPG/RANKL/RANK system consists of cytokines that play major roles in osteoclast formation. Therefore, our study selected the OPG/RANKL/RANK system as the research target to investigate the effect of ICA on nude mice with lung cancer bone metastasis. We established the model of bone metastasis in nude mice, intervened the model with icariin and zoledronic acid, and detected the levels of OPG and RANKL by ELISA and western blot. The results showed that ICA had a significant inhibitory effect on bone metastases in nude mice. ICA achieved its antibone metastasis effect in nude mice with lung cancer via inhibiting RANKL expression and simultaneously increasing OPG expression. ICA not only alleviated osteolytic bone destruction caused by bone metastases, but it also reduced weight loss in tumor-bearing nude mice at the late stage of the experiment. The role of ICA in preventing bone metastasis of lung cancer merits further investigation.

Therapeutic Potential of Liraglutide for Diabetes-Periodontitis Comorbidity: Killing Two Birds with One Stone.

Background: The relationship between diabetes and periodontitis is bidirectional, and there is now consensus that periodontitis and diabetes are comorbid. There is a quest for a drug that can be used to treat both conditions simultaneously. This study evaluated the anti-inflammatory and osteoprotective effects of liraglutide (LIRA) on periodontitis in diabetic rats. Methods: Male Wistar rats (n = 46) were randomly divided into four groups: control group (n = 8), LIRA group (n = 8), diabetes-associated periodontitis+0.9% saline group (diabetic periodontitis (DP)+NaCl group, n = 15), and diabetes-associated periodontitis+LIRA group (DP+LIRA group, n = 15). LIRA treatment lasted for 4 weeks (300 µg/kg/d) after establishment of a rat model of DP. The expression of IL-6, TNF-α, and IL-1ß was detected by enzyme-linked immunosorbent assay. The morphological changes of periodontal tissues were observed by hematoxylin-eosin staining. The absorption of alveolar bone and its ultrastructural changes were observed by histomorphometry and microcomputed tomography. The expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) in alveolar bone was detected by immunohistochemistry. The levels of Runx2 mRNA and ALP mRNA in the gingival epithelium were examined by quantitative real-time polymerase chain reaction. Results: LIRA decreased alveolar bone resorption, improved the microstructure of alveolar bone, and reduced periodontal inflammation and damage (P < 0.05). LIRA also reduced blood glucose level and inhibited the secretion of serum IL-6, TNF-α, and IL-1ß (P < 0.05). In addition, after treatment with LIRA, the ratio of RANKL/OPG was reduced, and the expression levels of ALP mRNA and Runx2 mRNA were upregulated (P < 0.05). Conclusions: LIRA not only controls blood glucose level but also reduces inflammation and bone loss and enhances osteogenic differentiation in diabetes-associated periodontitis. Those indicate that LIRA may be used as a potential medicine for the adjunctive therapy of diabetes-periodontitis comorbidity.

Synergistic enhancement of new bone formation by recombinant human bone morphogenetic protein-2 and osteoprotegerin in trans-sutural distraction osteogenesis: a pilot study in dogs.

PURPOSE: The previous decade has witnessed increasing emphasis on the technique of trans-sutural distraction osteogenesis (TSDO), a new and challenging procedure to reconstruct deficiencies in craniomaxillofacial bone. The purpose of this study was to determine if locally administered recombinant human bone morphogenetic protein-2 (BMP-2)/Poly(lactic-co-glycolic acid)/Fibrin sealant and recombinant human osteoprotegerin recombinant OPG fusion protein improves osteoblastogenesis and new bone formation by TSDO. MATERIALS AND METHODS: Thirty-two dogs were divided into 4 groups: control, BMP-2, OPG, or BMP-2 plus OPG. Two dogs from each group were sacrificed at 1, 2, 4, and 6 weeks after initiating the DO protocol. Immunohistochemical, histomorphometric, and electron microscopic assessments were performed to investigate the effects of BMP-2 or OPG induced by TSDO. RESULTS: The animals demonstrated significant overgrowth of the maxilla (control, 19.5 ± 2.61 mm; BMP-2, 19.9 ± 1.47 mm; OPG, 18.3 ± 1.2 mm; BMP-2 + OPG, 20.5 ± 2.65 mm). Histologically, the palatine suture widened dramatically within 2 weeks after distraction. Osteoblast number, trabecular thickness, content of alkaline phosphatase, and integrated optical density of BMP-2 increased obviously in the BMP-2 + OPG group (P < .05). CONCLUSIONS: TSDO in growing dogs is a safe, well-tolerated technology. The study found that OPG alone did not improve bone regeneration, but that it acted synergistically with BMP-2 to increase recruitment of mesenchymal stem cells and led to a significant enhancement of bone formation and healing. The temporal pattern of BMP-2 expression is consistent with a role in the regulation of mechanical and biological interventions designed to promote bone regeneration.

Juvenile Paget's Disease: Report of a successful treatment throughout the complete growth of a patient with a missense TNFRSF11B mutation.

INTRODUCTION: Juvenile Paget's Disease (JPD) is an ultra-rare inherited osteopathy featuring markedly accelerated bone turnover. Several clinical characteristics have been reported, including bone deformities developing in childhood and hearing loss. CASE REPORT: We report the case of a 2 ¾-year-old girl that presented with progressive bowing of both legs since the age of 2, lower limb pain and frequent falls with one consequent femur fracture. Plain radiographs revealed osteoectasia of the long bone's diaphysis, and laboratory tests showed extremely high serum total alkaline phosphatase levels. A missense mutation on the gene TNFRSF11B was identified in homozygosity, and the diagnosis of JPD was made. Treatment with bisphosphonates was initiated early and markedly improved lower limb bowing and pain. The patient reached adulthood with normal height, minor bone deformities, and no functional impairment. Despite the good skeletal symptom's response, bisphosphonates failed to prevent or improve sensorineural hearing loss. CONCLUSIONS: In this clinical case, early treatment with bisphosphonates was effective for the treatment of JPD skeletal deformities. New therapeutic strategies need to be developed to better control the extraskeletal manifestations of JPD.

Role of PDT as an adjunct to SRP on whole salivary RANKL and OPG ratio in type-2 diabetic and normoglycemic individuals with chronic periodontitis.

OBJECTIVE: The aim was to assess the effect of scaling and root planing (SRP) with and without adjunct photodynamic therapy (PDT) on the levels of osteoprotegerin (OPG) receptor activator of NF-kappa B ligand (RANKL) in the unstimulated whole saliva (UWS) of type-2 diabetic and normoglycemic individuals with chronic periodontitis (CP). METHODS: Type-2 diabetic and normoglycemic subjects with CP (Groups 1 and 2, respectively) were divided into test- (SRP + PDT) and control (SRP only) groups. Patient demographics were recorded; and periodontal parameters (marginal bone loss [MBL], probing depth [P.D], plaque index [PI], gingival index [GI], and clinical attachment loss [CAL]) were assessed at baseline and at 3-months-follow-up. Rate of flow of unstimulated whole saliva and levels of RANKL and osteoprotegerin were measured at both time intervals. P < 0.05 was considered statistically significant. RESULTS: Eighty-four persons with CP (42 with and 42 without type-2 DM) were included. At baseline, clinicoradiographic parameters were comparable in all groups. At 3-months of follow-up, there was no significant difference in the clinicoradiographic parameters in all groups. At 3-months of follow-up, there was no significant reduction in whole salivary RANKL and osteoprotegerin levels among individuals in the test and control groups among CP patients with and without CP. CONCLUSION: The whole salivary RANKL/OPG ratio remains high in patients with poorly-controlled type-2 DM after SRP with or without adjunct PDT.

Expression of angiogenesis-related proteins in bone marrow mesenchymal stem cells induced by osteoprotegerin during osteogenic differentiation in rats.

This study aimed to discuss the expression of angiogenesis-related proteins in bone marrow mesenchymal stem cells (BMSCs) induced by osteoprotegerin (OGP) during osteogenic differentiation in rats, and to analyze the effect of fracture healing inflammatory factor TNF-ɑ on the osteogenic differentiation of BMSCs of rats. BMSCs isolated and cultured from the third generation rats were taken as the research object. According to the addition amount of OGP, BMSCs were divided into control group, OGP (10-7 mol/L) group, OGP (10-8 mol/L) group, and OGP (10-9 mol/L) group. The cell growth and morphological characteristics of each group were observed by inverted phase contrast microscope, the cell proliferation rate was measured by MTT method, angiogenesis-related markers (platelet growth factor (VEGF), cingulate protein 5 (Fbln5), and angiogenin-like protein 4 (Angptl4)) were quantitatively detected by Western blot, and the effect of TNF-ɑ on osteogenic differentiation was detected by CCK. Compared with the control group, MTT results showed that the value-added rate of cells in the OGP (10-8 mol/L) group reached the maximum at 9 days (P < 0.05). The ALP activity in osteoblasts in the OGP (10-8 mol/L) group reached the maximum at 9 days (P < 0.01). The OGP (10-8 mol/L) group had the highest expression of vascular regeneration proteins (VEGF, Fbln5, and Angptl4) (P < 0.05). CCK analysis showed that the TNF-ɑ (1.0 ng/mL) group showed a significant increase in absorbance compared with the control group on 6 days (P < 0.05), and the OD value of the TNF-ɑ (10 ng/mL) group decreased at all time points (P < 0.05). Overall, 10-8 mol/L OGP can induce the proliferation and osteogenic differentiation of MSCs, and promote the expression of angiogenesis-related proteins (VEGF, Fbln5, and Angptl4) during osteogenic differentiation. Besides, 1.0 ng/mL of TNF-ɑ can also promote osteogenesis differentiation of BMSCs in the short term.

Combination therapy with dexamethasone and osteoprotegerin protects against arthritis-induced bone alterations in antigen-induced arthritis of the rat.

OBJECTIVE: To investigate the influence of a combined therapy consisting of dexamethasone and osteoprotegerin (OPG) on bone alterations and disease activity in antigen-induced arthritis (AIA) in the rat. METHODS: AIA rats received dexamethasone (0.25 mg kg(-1) day(-1), i.p.), OPG (2.5 mg kg(-1) day(-1), i.p.), or a combination of both at regular intervals for 21 consecutive days. At the end of the treatment, bone structure was analyzed by histomorphometry. Primary spongiosa was measured using linear scanning. RESULTS: AIA led to significant periarticular and axial bone loss. Dexamethasone monotherapy substantially suppressed joint swelling without inhibiting bone loss of the secondary spongiosa, whereas OPG monotherapy showed no anti-inflammatory effect. Despite reduction of bone resorption, OPG did not inhibit AIA-induced bone loss. In contrast, the combination of dexamethasone and OPG not only produced an anti-inflammatory effect, but also resulted in inhibition of periarticular and axial bone loss. OPG increased trabecular number of the primary spongiosa whilst combination therapy led to an increase in both trabecular number and trabecular width. CONCLUSION: The principle of combining a glucocorticoid together with inhibition of the receptor activator of NF-kappaB ligand (RANKL) may be an effective bone-saving therapy in rheumatoid arthritis.